Gentoo noob here. My first attempt at installing (using install-amd64-minimal-20141113 and stage3-amd64-nomultilib-20141113) has hit a problem. Using mirrorselect to append GENTOO_MIRRORS and SYNC info to /mnt/gentoo/etc/portage/make.conf isn't working as it silently fails to write to the file. The mirrorselect chooser screen shows the list of URLs, but the URL names are truncated so I can't see what to add manually to make.conf.

Anyone got examples of URLs for GENTOO_MIRRORS and SYNC that work? (UK mirrors preferred, but anything that works will do). Thanks.